In a turbine installation which has a gas turbine engine acting as a generator for hot gas to power a free turbine, the turbine intermediate case is located downstream of the gas generator turbine stages and between them and the free or power turbine. This case provides a bearing support for the rear bearing of the low pressure turbine shaft and the front bearing for the free turbine. This case is subjected to severe thermal gradients during both transient conditions and steady state operation and requires controlled cooling in order to maintain concentricity both under steady state conditions and under transient conditions. This cooling is particularly necessary in order to provide the long life required in turbine installations, for example in commercial electrical generating systems.